The SS Xhosa was an Antares-class cruiser, which according to its dedication plaque, was constructed at the Luna Shipyards during the 23rd century. By 2371, the Xhosa was commanded by the civilian Captain Kasidy Yates.
The ship's equipment was mostly obsolete, provided by the Petarians. As such it only had a Mark V transporter, requiring ship's personnel to use anti-grav sleds when loading the ship with unstable biomatter. (DS9: "Family Business")
In 2371, the Xhosa operated under the authority of the Petarians. (DS9: "Family Business") On Stardate 48960.9, the Xhosa hauled a load of duridium ore to Solais V. The ship was due to return to Deep Space 9 the following month. (DS9: "The Adversary")
When a Klingon task force arrived in the Bajoran system in early 2372, a Klingon Bird-of-Prey, the IKS M'Char, stopped the Xhosa and attempted to board it to search for Changelings while attempting to leave the system. Trapped in the M'Char's tractor beam, its Commander Kaybok, insisted that the freighter must be searched, under orders from Chancellor Gowron and the Klingon High Council. They were approached by the USS Defiant, which eventually forced the M'Char to withdraw and the Xhosa left the Bajoran system for approximately two weeks. The Xhosa later returned to Deep Space 9 for a one-day layover before departing again for its next haul. (DS9: "The Way of the Warrior")
The Xhosa later delivered emergency supplies to a Maquis raider located in the Badlands. Before returning to Deep Space 9 one last time, Yates offloaded her crew and return to the station aboard the Xhosa alone, to face the consequences of her actions. (DS9: "For the Cause")
- See: SS Xhosa personnel
The name "Xhosa" came from a tribe indigenous to South Africa known as the Xhosa people. In real life, the word begins with a lateral click not present in English. According to the scripts for "The Way of the Warrior"  and "For the Cause",  the word was pronounced "ZOE-sa". The Star Trek Encyclopedia suggests "Zosha" as the pronunciation. In older Afrikaans, it was sometimes written as "Kôsa". In South Africa, it was, accordingly, often pronounced as "CAW-zah", the voiceless, velar plosive "k" approximating the lateral click. Nelson Mandela was of Xhosa descent.
According to the script notes from "Family Business", Kasidy's ship was an "independent interstellar freighter." 
During the Typhon Pact novel Plagues of Night, the Xhosa was destroyed with all hands when a Tzenkethi ship collided with it, causing it to explode. Captain Yates-Sisko and Vedek Kira Nerys had left moments before, boarding Deep Space 9 to help an ongoing evacuation. However, the station itself was destroyed by a reactor breach seconds later, as Captain Benjamin Sisko watched from the bridge of his new starship, the Galaxy-class USS Robinson (β).
The novelization of The Way of the Warrior featured scenes set aboard the Xhosa.